Great progress Frederik, I'm also watching very closely. Are you glueing the two layers of plywood together with (lots of) epoxy? I've wondered about using a PU (D4) glue for this, it's cheaper and gap filling and it's probably what the ply is made from but it may be impossible to work with big sheets of ply fast enough and it won't seal the ply as well as epoxy. Anyone else have thoughts on this?
Also, I'm intrigued by Chris Morejohn successfully going against all advice I've ever seen (including his friend Reuel Parker) and using polyester resin over plywood. Any thoughts on this?